Isolation of 3beta,7alpha-dihydroxychol-5-enoic acid, an intermediate of chenodeoxycholic acid biogenesis, and 3alpha,7alpha-dihydroxychol-4-enoic acid from bladder bile of hens.

Two Lifschütz-positive C24-bile acids were isolated from bladder bile of hens. One of these was identified by isotope dilution experiments after conversion to a 3H-labeled compound, and also by GLC after methoxylation, as 3beta,7alpha-dihydroxychol-5-enoic acid, a key intermediate of chenodeoxycholic acid biogenesis. The other, to which the structure 3beta,7alpha-dihydroxychol-4-enoic acid had been assigned previously, was proved to be its 3alpha-epimer by several experiments. These findings favor the alternative pathway of chenodeoxycholic acid biogenesis proposed by Yamasaki and his associates.